Medical slings

ABSTRACT

A medical sling made from material that is suitably shaped for use in a medical application has sides, portions of which are smoothed to prevent abrasion of surrounding tissue.

[0001] This application claims priority to provisional patentapplication Ser. No. 60/274,843 filed in the U.S. Patent Office on Mar.9, 2001 and provisional patent application Ser. No. 60/286,863 filed inthe U.S. Patent Office on Apr. 26, 2001, the entire contents of whichare incorporated by reference herein.

TECHNICAL FIELD

[0002] This invention generally relates to surgical mesh for use as amedical sling, such as a pelvic floor repair mesh, methods of makingsuch mesh, kits including such mesh, and methods of treating orreinforcing a damaged, prolapsed, weakened or herniated portion of apatient's body using such mesh.

BACKGROUND INFORMATION

[0003] Surgical prosthetic mesh has been used to treat or reinforcetissues or organs which have been damaged, prolapsed, weakened, orotherwise herniated, such as in the conditions rectocele, cystocele,enterocele, vaginal prolapse, and protocele, for example. A prolapserefers to the slipping down of an organ or organ part from its normalposition. For example, a prolapse of the rectum refers to the protrusionof the inner surface of the rectum through the anus. Rectocele is theprolapse of the rectum into the perineum. A prolapse of the uterusrefers to the falling of the uterus into the vagina due to stretchingand laxity of its supporting structures. Vaginal vault prolapse refersto the prolapse of the cephalad extreme of the vaginal canal toward,through, and beyond the introitus. Cystocele (i.e., vesicocele) is ahernia formed by the downward and backward displacement of the urinarybladder toward the vaginal orifice, due most commonly to weakening ofthe musculature during childbirth. However, any abnormal descent of theanterior vaginal wall and bladder base at rest or with strain isconsidered cystocele. Enterocele is a hernia of the intestine, thoughthe term is also used to refer specifically to herniation of the pelvicperitoneum through the rectouterine pouch (i.e., posterior vaginal,rectovaginal, cul-de-sac, or Douglas' pouch hernia).

[0004] Surgical mesh may also be used to suspend tissues or retract bodyorgans temporarily, e.g., during surgery. For example, U.S. Pat. No.4,973,300 describes the use of a cardiac sling for supporting the heartduring surgery; and U.S. Pat. No. 5,362,294 describes the retraction ofbody organs such as the uterus or bowel during laparoscopic surgery;U.S. Pat. No. 6,102,921 describes the use of a medical anastomosis slingfor the use in repair or regeneration of nerves.

[0005] Synthetic mesh materials utilized as slings for the treatment orreinforcement of patient tissues for these and many other conditions cancause patient complications such as erosion, due at least in part to thesharp tangs on the edges of the mesh, which are formed during themanufacturing process or afterward (for example, when a physician cutsor shears or otherwise shapes the material). These tangs can cause anirritative effect which can lead to an erosion when they contactsurrounding tissue. Thus, a need exists for a sling which minimizesirritation and erosion of the tissue surrounding the tissue which itsupports.

[0006] Stress urinary incontinence (SUI), which primarily affects women,is a condition which is successfully treated using surgical slings.Stress urinary incontinence is generally caused by two conditions thatmay occur independently or in combination, namely, intrinsic sphincterdeficiency (ISD) and hypermobility. In ISD, the urinary sphincter valve,located within the urethra, fails to close properly (coapt), causingurine to leak out of the urethra during stressful actions. Hypermobilityis a condition in which the pelvic floor is distended, weakened ordamaged, causing the bladder neck and proximal urethra to rotate anddescend in response to increases in intra-abdominal pressure (e.g., dueto sneezing, coughing, straining, etc.), resulting in insufficientresponse time to promote urethral closure and, consequently, in urineleakage and/or flow.

[0007] Biological factors that can affect hypernobility include: poorendopelvic fascia muscle tone (from age or limited activity), endopelvicfascia muscle stretch/tear from trauma (e.g. childbirth), endopelvicfascia/arcus tendenious (muscle/ligament) separation (lateral defect),hormone deficiency (estrogen), concombinant defects (cystocele,enterocele, ureteral prolapse), and vaginal prolapse. Traditionaltreatment methods include bladder neck stabilization slings in which asling is placed under the urethra or bladder neck to provide a platformpreventing over distention. An emerging alternative treatment is theplacement of a mid-urethral sling. Such a sling placement takesadvantage of the hypermobility condition by providing a fulcrum aboutwhich the urethra and bladder neck will rotate and provide a “urethralkink” to assist normal urethral closure.

[0008] Slings are traditionally placed under the bladder neck to providea urethral platform limiting endopelvic fascia drop while providingcompression to the urethral sphincter to improve coaptation. Themid-urethral placement location provides mechanical stability to a lessmoveable anatomical structure. Bladder neck slings have traditionallybeen affixed in the desired location using a bone anchoring method.Mid-urethral slings, being placed in a low mobility area, havedemonstrated the effectiveness of an anchorless approach. Recognizingthat minimal tension, if any, is necessary, a physician need only placethe sling under the mid-urethra secured through the endopelvic fascia topermanently secure the sling in position. The sling permits immediatetissue security through the mesh openings and mesh tangs to initiallymaintain sling stabilization. As healing occurs, the endopelvic fasciaand rectus fascia tissue re-establish vascularity and regrow into andaround the knit pattern of the mesh. The sling in this procedureprovides a fulcrum about which the pelvic floor will drop (takingadvantage of the hypermobility condition of the patient) and a urethral“kink” or higher resistance to obstruct urine flow during high stressconditions.

[0009] Thus, while tangs can contribute beneficially to SUI treatment,they can also cause patient complications such as erosion of the vaginaor urethra.

SUMMARY OF THE INVENTION

[0010] The present invention relates to surgical mesh or slings with anon-tanged (i.e., tangs are unformed, smoothed, rounded, or removed)section disposed on a portion of the sides of the mesh, methods ofmaking such mesh, medical kits including such mesh, and methods oftreating a damaged, weakened, sagging, herniated or prolapsed portion ofa patient's body using such mesh.

[0011] The benefits of such a sling according to the invention includedecreased tissue irritation from a non-tanged section when it is incontact with tissue, such as urethral and vaginal tissue, whilepromoting rapid scar tissue formation around the tanged portion of thesling. The formation of scar tissue generally adds bulk that compressesthe tissue to which it is applied (e.g., the urethra), provides supportto improve patient continence and inhibits or prevents movement of theplaced sling following placement.

[0012] In one aspect, the invention involves a sling for use in amedical application. The sling is made of a mesh material that includesfirst and second opposed ends (i.e., disposed opposite and away fromeach other) along a longitudinal axis. The mesh material also includesfirst and second opposed sides separated by a distance along an axisperpendicular to, or substantially perpendicular to, the longitudinalaxis. The perpendicular axis intersects the longitudinal axis at themidpoint, or substantially at the midpoint, of the perpendicular axis. Aportion of the first and second sides and the first and second ends ofthe material contains tangs. A portion of the first and second sidesdoes not contain tangs (e.g. tangs on the first and second sides areunformed, smoothed, rounded or removed), creating a non-tanged section.The first and second sides may each have, for example, a non-tangedsection about 1 cm to about 5 cm in length, centered along thelongitudinal axis.

[0013] The sling of the invention may have a shape suitable for amedical application; e.g., it may be rectangular or substantiallyrectangular. Alternatively, the sling may be octagonal, hexagonal,trapezoidal, elliptical, or some other shape that is suitable to thesling's intended placement location within the body.

[0014] In another aspect, the invention relates to a method of making asling by direct manufacturing with a non-tanged section or by smoothing,rounding or removing the tangs on a portion of the sling to create anon-tanged section.

[0015] The sling material provided may be derived from syntheticmaterials or a combination of mammalian tissue(s) and syntheticmaterial(s). The method of making the sling can further comprisesterilizing the sling material according to methods known in the art sothat the sling is suitable for use in various medical applications, andmay include packaging the sling in a sterile holder. The sling materialmay be enclosed within a sleeve to assist in handling the sling and/orto adjust the sling during surgical placement, or to prevent the slingfrom stretching or becoming misshapen due to handling prior to placementwithin the body of the patient.

[0016] In a further aspect, the invention involves a method of treatinga damaged portion of a patient's body using a sling with a non-tangedsection. The sling is placed inside the body of a patient such that itsperpendicular axis lies substantially along a portion of the patient'sbody, such as the mid-urethra, bladder, rectum, vagina, blood vessel,nerve, heart, etc.; the material supports a portion of the patient'sbody in a manner which does not erode the surrounding tissue. The slingmay be centered at the damaged portion of a patient's body using theperpendicular axis of the sling as a guide. Pressure may be distributedevenly on a portion of a patient's body with the secured sling material.A surgical fastener such as a suture, a clip, a bone anchor, a staple,or other suitable fastener, may be employed to secure the sling toanatomical structures.

[0017] The sling material may be implanted to treat female urinaryincontinence according to transvaginal, transabdominal, or combinedtransvaginal and transabdominal procedures. For example, the method maybe employed to treat a patient with SUI, the non-tanged section of thesling placed adjacent the patient's mid-urethra.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In the drawings, like reference characters generally refer to thesame parts throughout the different views. The drawings are notnecessarily to scale, but rather illustrate the principles of theinvention.

[0019]FIG. 1 is a plan view of a rectangular embodiment of a slinghaving a non-tanged section on either side of the perpendicular axis.

[0020]FIG. 2 is a close-up diagram of sling material with a non-tangedsection.

DESCRIPTION

[0021] Referring to FIG. 1, a sling 20 in accordance with the presentinvention can be made of one or more materials 22, and includes a firstend 24 and a second end 26. The second end 26 is disposed opposite andaway from the first end 24 along a longitudinal axis 28. The material 22also includes a first side 30 and a second side 32. The second side 32is disposed opposite and away from the first side 30 along aperpendicular axis 34. The axis 34 is perpendicular to, or substantiallyperpendicular to, the longitudinal axis 28, and intersects thelongitudinal axis 28 at the midpoint, or substantially the midpoint, ofthe axis 28. The longitudinal axis 28 of the sling 20 may range fromabout 2.5 cm to about 45 cm in length, while the perpendicular axis 34may range from about 1.0 cm to about 3.0 cm. The sling is preferably 20to 30 cm in length and 1 to 3 cm wide, though larger and smaller slingsare contemplated depending upon the size of the patient and the surfacearea of the body part that requires support.

[0022] The sling 20 and 21 can be rectangular, as illustrated in FIG. 1,or substantially rectangular in shape (e.g., octagonal). Alternatively,the sling may have another shape (e.g., trapezoidal, hexagonal, orelliptical) suitable to its intended placement location within the body.Exemplary shapes are described in U.S. Pat. No. 6,042,534, thedisclosure of which is incorporated herein by reference.

[0023] The thickness of the sling material 22 can be uniform over theentire piece of the material or it can vary at one or more differentlocations. The thickness of sling material 22 may range from about 0.02to about 0.10 cm, but typically will be about 0.07 cm and have a uniformthickness. The material construction may impact the material thicknessand uniformity; for example, a weave may have thicker regions where thefibers intersect.

[0024] The mesh may have any of a number of knits, weaves, or braids,such as those described in U.S. Pat. Nos. 5,569,273; 5,292,328;5,002,551; 4,838,884; 4,655,221; 4,652,264; 4,633,873; 4,520,821;4,452,245; 4,347,847; 4,193,137; 5,124,136; 3,054,406; and 2,671,444 thedisclosures of which are hereby incorporated by reference.

[0025] The mesh material may be fabricated from any of a number ofbiocompatible materials such as nylon, polyethylene, polyester,polypropylene, fluoropolymers, copolymers thereof, combinations thereof,or other suitable synthetic material(s). The material may be, forexample, a synthetic material that is absorbable by the patient's body.Suitable absorbable synthetic materials include polyglycolic acid,polylactic acid, and other suitable absorbable synthetic materials. Themesh material may be fabricated from one or more yams, which yams may bemade from one or more materials. The mesh may be produced according tonumerous fabrication processes, and may be designed to permit rapidtissue revascularization and tissue in-growth by having largeinterstitial spaces. For example, each yam of the mesh may have voidareas between yarn filaments and the fabrication process may createcrevices. An exemplary weave is a tricot knit with two yams per needle,as illustrated in FIG. 2. In a preferred embodiment, the mesh iscomposed of polypropylene monofilament yarns.

[0026] Absorbable synthetic materials may also be suitable for use inaccordance with the invention. Such absorbable synthetic materialsinclude, for example, polyglycolic acid (PGA), polylactic acid (PLA),and other available absorbable synthetic materials. A suitable PGAmaterial is available under the trade designation DEXON, from TYCO.Other suitable polymeric and non-polymeric synthetic materials may beemployed in accordance with the invention. Exemplary materials as setforth above are found in U.S. Pat. Nos. 6,090,116; 5,569,273; 5,292,328;4,633,873, 4,452,245; 4,347,847; 3,124,136; 3,054,406; and 2,671,444,and Inglesia, C. B. et al. (1997) Int. Urogynecol. J. 8:105-115, theentire disclosures of which are incorporated by reference.

[0027] Alternatively, the sling material 22 may be derived from acombination of mammalian tissue(s) and synthetic material(s). Themammalian tissue source may be, for example, human, human cadaveric, ortissue-engineered human tissue. The mammalian tissue may alternativelybe from an animal source such as porcine, ovine, bovine, and equinetissue sources. Such combinations may also include materials thatinclude both synthetic polymers and animal cells that are treated so asto cross-link the collagen or other commonly antigenic fibers of theanimal cells. In one embodiment, at least a portion of the mesh portionof the sling which contacts the patient's tissue comprises a syntheticmaterial requiring smoothness of the tangs.

[0028] The tangs (i.e., sharp projections or frayed edges) 40 that formwhen the material 22 is cut, chopped, torn, frayed or otherwisemanufactured may be located along any edge of the material 22. The tangs40 are generally useful for encouraging tissue growth into the material22. However, it is found that some tangs 40 may erode the adjacenttissue when the sling 20 is inserted into a patient's body. Accordingly,a portion of the tangs 40 located on sides 30 and 32 (e.g., in someembodiments to within about 1 cm to about 5 cm of either side of theperpendicular axis 34) are therefore unformed, smoothed, rounded orremoved to form a non-tanged section 42. By removing these irritativeprojections, which will be in close proximity to the urethra andanterior vaginal wall, the erosion effects are reduced.

[0029] With continued reference to FIG. 1, in one version of the sling,a line 36 is disposed along the perpendicular axis 34 of a rectangularsling 20. The line 36 may be formed by, for example, applying surgicalink along the perpendicular axis 34 of the material 22. Preferably, theapproximate midpoint of the non-tanged sections 42 of sides 30 and 32intersects with line 36. Thus, line 36 may be employed as a visual guideto evenly align the non-tanged sections 42 with the portion of thepatient's body that the sling 20 is employed to support.

[0030] Any process which will smooth, round or remove the tangs 40 toremove their sharp edges is suitable. For example, the tangs 40 may beheat smoothed by burning or melting. Such a heat process causes meltingof the sharp tangs 40 back to the woven knot 44 forming a non-tangedsection 42, as shown best in FIG. 2. The non-tanged section 42 may belocated on both sides 30 and 32, occupying, for example, about 1 to 4 cmon either side of the perpendicular axis 34. The tangs may be removed,for example, along a 5, 6, 7, 8, 9 or 10 cm portion of the side of themesh material.

[0031] An exemplary method of making a sling 20 of the invention from amaterial 22, for example, includes manufacturing a sling material 22 andforming a non-tanged section 42 on a portion of a material 22 at sides30 and 32 adjacent the perpendicular axis 34. The sling 20 may be formedfrom the cutting to size of a larger piece of sling material 22. Thetangs 40 on a portion of each side 30 and 32 are unformed, smoothed,rounded or removed (e.g., to the woven knots) to form a non-tangedsection 42. The non-tanged section 42 may span a segment of sides 30 and32 having a length up to about 4 cm, but usually at least about 1 cm,and the segment is preferably centered on the perpendicular axis 34. Inalternative embodiment, the non-tanged section 42 may span a segment ofsides 30 and 32 having a length of 5, 6, 7, 8, 9 or 10 cm. In oneversion of the method, the tangs 40 are smoothed, rounded or removed byexposing the tangs to a source of heat (i.e., by contact or by bringingthe heat source into close proximity to the tangs). In an alternativemethod, a straight blade edge that is heated to a sufficient temperatureto simultaneously cut and smooth the tangs 40 may be employed.

[0032] The sling 20 may be surrounded by or enclosed within a sleeve orenvelope as described in the U.S. patent application entitled “Systemfor Implanting an Implant” co-filed with the instant application, whichis hereby incorporated by reference in its entirety. The co-filedapplication also contains methods for installing slings enclosed withinan envelope.

[0033] Referring to FIG. 1, the sling 20 may be pre-soaked in aprescribed drug prior to implantation in a patient's body. Exemplarydrugs include neomycin, sulfa drugs, antimicrobials, and antibiotics,generally. In some embodiments, the hydrophilic material, the drug, orboth when used in combination, release the drug to patient tissues uponcontact. Thus, the drugs that are delivered to the patient tissuesurfaces when accessing and inserting the sling 20 are active uponcontact with the patient's tissue during implantation of the surgicaldevice.

[0034] Alternatively, the sling 20 is made of a non-wettable materialsuch as a polypropylene, polyethylene, polyester,polytetrafluoroethylene, TYVEK®, MYLAR®, or co-polymers thereof.Polytetrafluoroethylene which is suitable for use in accordance with thepresent invention, is available from DuPont (Wilmington, Del., under thetrade designation TEFLON®). Such non-wettable materials do not take upany liquids, for example, drugs in solution. In order to permit drugs tobond or absorb to these non-wettable material surfaces, the sling 20 canbe treated with a substance that is wettable such as, for example, awettable coating composition. The wettable coating composition may be asynthetic coating (e.g., polyvinylperilidone or PVP), a natural coating(e.g., collagen) or a physically absorbent material (e.g., spongecomprising cellulose or open celled polyurethane). The wettable coatingcomposition may be hydrophilic, so as to pick up or absorb hydrophilicdrugs. Suitable hydrophilic coatings may be water soluble and include,for example, Hydroplus (Boston Scientific Corp., Natick, Mass.),Hydropass (Boston Scientific Corp., Natick, Mass.), hyoscymine sulfate,which is available under the trade designation CYTOSPAZ from Polymedica(Woburn, Mass.), and ketrodac fromethamine, which is available under thetrade designation Toradol from Roche Pharmaceuticals (Nutley, N.J.).Hydrophilic drugs that may be employed in accordance with the inventioninclude oxybutynin chloride, lidocaine, ketorolac, and hyoscyminesulfate, for example.

[0035] Similarly, a hydrophobic coating may be employed on one or moresurfaces of the sling 20. Suitable hydrophobic coatings include but arenot limited to hydrophobic coatings that may be employed in accordancewith the invention include polytetrafluoroethylene, silicon, andPyrelene. Such hydrophobic coatings may be used in conjunction with andabsorb hydrophobic drugs. Suitable hydrophobic drugs include but are notlimited to suitable hydrophobic drugs include ibuprofen, ketoprofen,diclofenac, and lidocaine in hydrophilic form. Where the bonding betweenthese coatings and drugs is weak, the drug that is absorbed will readilyrelease to be delivered to the surfaces it contacts. Alternatively, astronger bonding affinity may provide a slower timed release of thedrug.

[0036] Where the coating applied to the surface of the sling 20 has anionic charge, drugs comprising a complementary charge will bond to thecoating when the coating and the drug are exposed to one another. Thestrength of any bonding will impact how readily the drug is releasedfrom the surface of the sling 20. Where the ionic bonding between thecoating and the drug is weak, the drug will release more readily. Inembodiments where rapid drug release is desirable, covalent bondingbetween the surface coating and the drug should be avoided.

[0037] Alternatively, the sling 20 may be coated with hydrophiliccoating 75. The sling 20, coated with hydrophilic coating 75, may bedipped into a solution containing a hydrophilic drug just prior tosurgery. In another embodiment, the hydrophilic coating and thehydrophilic drug are mixed to form a single coating. This coating may bedisposed on the surface of the sling 20.

[0038] Methods of sling delivery and installation, e.g., to treat femalestress incontinence include but are not limited to transvaginal,transabdominal (percutaneous), and combined transvaginal andtransabdominal procedures.

[0039] Variations, modifications, and other implementations of what isdescribed herein will occur to those of ordinary skill in the artwithout departing from the spirit and the scope of the invention.Accordingly, the invention is not to be limited by the precedingillustrative description.

What is claimed is:
 1. A sling for use in a medical application, the sling comprising a material including (a) a first end and a second end, the second end being disposed opposite and away from the first end along a longitudinal axis; and (b) a first side and a second side, the second side being disposed opposite and away from the first side by a distance and along an axis that is substantially perpendicular to the longitudinal axis, wherein a portion of the first side and the second side is non-tanged.
 2. The sling of claim 1, wherein the non-tanged portion of first side and the second side is about 3 cm and is centered over the perpendicular axis.
 3. The sling of claim 2, wherein the non-tanged portion of first side and the second side is about 1 cm and is centered over the perpendicular axis.
 4. The sling of claim 3, wherein the non-tanged portion of first side and the second side is about 0.5 cm and is centered over the perpendicular axis.
 5. The sling of claim 1, wherein the non-tanged section is heat-smoothed.
 6. The sling of claim 1, wherein a portion of the first and second sides is tanged.
 7. The sling of claim 1, further comprising a visible line disposed substantially along at least a portion of the perpendicular axis as a visual guide.
 8. The sling of claim 7, wherein the line comprises a surgical ink.
 9. The sling of claim 1, wherein the material comprises synthetic material.
 10. The sling of claim 9, wherein the synthetic material is at least one of nylon polyethylene, polyester, polypropylene, fluoropolymers or a co-polymer thereof.
 11. The sling of claim 1, wherein the material has a substantially rectangular shape.
 12. The sling of claim 1, wherein the sling is surrounded by a sleeve comprising an inner surface and an outer surface.
 13. A method of making a sling, the method comprising the steps of: providing a material in a shape suitable for a medical application, the material including (a) a first end and a second end, the second end being disposed opposite and away from the first end along a longitudinal axis, and (b) a first side and a second side, the second side being disposed opposite and away from the first side by a distance and along a perpendicular axis that is substantially perpendicular to the longitudinal axis, and that intersects the longitudinal axis at substantially a midpoint thereof, and (c) tangs projecting from the first and second sides; and smoothing, rounding or removing the tangs along a portion of the first side and the second side to form a non-tanged section on each side.
 14. The method of claim 13, wherein said smoothing step is achieved by heat treatment.
 15. A method of treating a damaged portion of a patient's body using a sling comprising inserting into a patient at a damaged portion of the patient's body a material including: (a) a first end and a second end, the second end being disposed opposite and away from the first end along a longitudinal axis; and (b) a first side and a second side, the second side being disposed opposite and away from the first side by a distance and along an axis that is substantially perpendicular to the longitudinal axis, wherein a portion of the first side and the second side is non-tanged.
 16. The method of claim 15, wherein the sling is centered at the damaged portion of the patient's body using the perpendicular axis of the sling as a guide.
 17. The method of claim 15, wherein pressure is distributed evenly on the damaged portion of the patient's body.
 18. The method of claim 15, wherein the patient suffers from stress urinary incontinence. 